The present invention is directed to novel louvered assemblies for window coverings, and more particularly relates to multilayer verticle louver assemblies having an improved pearlescent outer layer.
Over the last few decades, vertical louvered systems have become popular. Typical vertical louvered assemblies comprise relatively thin, elongated vertical hanging slats which are suspended and depend vertically from a mechanism which aligns and orients the slats. Typically the depending slats overlap slightly and can be rotated in unison to infinitely adjust the light or view through the opening. The slats are made from a wide variety of materials including extruded vinyl strips and are optionally decorated by attanching webs, narrow woven or slit fabrics, or laminated films.
Related to the present invention are vertical slat assemblies involving combinations of a slat member and a decorative member which is inserted thereupon to the face, back or both sides of the slat with attachment means. The vertical louver described in U.S. Pat. No. 4,049,038 ('038) comprises lateral inwardly facing attachment means which are flanges on one or both faces of the slat which will receive an insert such as a strip of wallpaper or fabric. U.S. Pat. No. 4,628,980 ('908) discloses a louver of identical shape to '038 but incorporates co-extruded transparent flanges. The patentable difference between '038 and '980 is the transparency of the lateral flanges which are less obtrusive. In commercial practice, such louvers are made by the co-extrusion of a clear thermoplastic compound for the lateral flanges with an opaque compound for the rest of the slat.
A material of choice for co-extruded louver slats of this type is polyvinyl chloride due to the favorable cost/performance properties of this commodity thermoplastic resin.
U.S. Pat. No. 4,195,680 discloses decorative attachments to an '038 flanged louver comprising one or more multiple clear or translucent tinted film inserts which allow convenient color changes. Variations in color are achieved by attaching one or more inserts each of which have different colors and together form a new color.
A pertinent reference relative to the present invention, U.S. Pat. No. 4,877,077 ('077) discloses a vertical louver made from co-extruded vinyl thermoplastic wherein a transparent outer layer containing a pearlescent pigment is co-extruded with an opaque base layer. The opaque base layer is visible and reflects light through the peralescent surface layer. Optionally a transparent or translucent tinting color dye is incorporated in the outer layer.
The approach disclosed in '077 has several shortcomings. First, due to the restriction of transparency, the resulting perceived color of the pearlescent surface is a combination of the colors making up the transparent layer and the color of the opaque base layer. The appearance of the louvers are sensitive to minute variations in the coating thickness which can create the appearance of undesirable streaking for instance. Imperfections in the consistency of the extruded compound such as polymer gells are more likely to occur in compounds having low filler or pigment levels in the pearlescent layer yet the '077 patent teaches the requirement of using a clear transparent compound in order to provide the basis for obtaining a pearlescent effect.
Secondly, transparent thermoplastic materials including vinyl based polymers are susceptible to degradation and yellowing when exposed to ultraviolet radiation from the sun or fluorescent lights if not adequately protected. This is particularly problematic where sections of the louver ensemble receive varying levels of exposure. Non-uniformity in the thickness of a transparent outer layer can lead to perceptible streaking after yellowing occurs even where the entire surface has been uniformly exposed.
Accordingly, it would be desirable to devise a pearlescent multilayered louver not having the aformentioned drawbacks.